1. Field of the Invention
The present invention relates to a lightweight V-grooved pulley and, more particularly, to a lightweight V-grooved aluminum alloy pulley easily formed from plate and having a high mechanical strength, in which the V-grooved portion has excellent wear resistance.
2. Description of the Related Art
A so-called V-grooved pulley 1 having a substantially V-shaped section, as shown in FIG. 1, is conventionally manufactured in accordance with two methods. According to the first method, a steel mass is cut to obtain a final shape as shown in FIG. 1. According to the second method, a steel plate is worked out as shown in FIGS. 2A to 2E. A steel plate blank 20 as shown in FIG. 2A is drawn to form a cylindrical member 21 having one open end, as shown in FIG. 2B, and the cylindrical member 21 is further drawn to fabricate a cup-shaped member 22 as shown in FIG. 2C. A circumferential surface 22a of the cup-shaped member 22 is subjected to rotational formation to form grooves 23 each having a substantially V-shaped section to obtain a final V-grooved pulley in which a bottom surface 22b of the cup-shaped member 22 has a disk-like shape, as shown in FIGS. 2D and 2E. According to the second method, a lighter V-grooved pulley can be obtained compared to the first method, since the pulley is fabricated from the steel plate. However, a further decrease in weight of the V-grooved pulley is demanded. To meet this demand, a method of using a high-strength material to decrease the thickness or a method of substituting a steel with a lighter material may be possible.
In general, however, when the strength of the material is increased, formability is degraded; when the formability of the material is improved, the mechanical strength is decreased, leading to a contradictory problem. Hence, a lightweight V-grooved pulley satisfying the both characteristics does not conventionally exist.